Sand dams providing clean water in Zimbabwe: meeting WHO standards

Recent evidence from Excellent Development’s partners in Zimbabwe show how sand dams have improved the quality of water for dryland communities in the region...

A sand dam is a reinforced concrete wall built across a seasonal sandy river. They are the cheapest method of conserving water in drylands – providing an improved, reliable source of water close to people’s homes.

During the rainy season, a seasonal river forms that carries soil (made up of silt and sand) downstream. The heavier sand accumulates behind the dam, whilst the lighter silt is carried downstream.

Within one to four rainy seasons, the dam fills with sand. But, up to 40% of the volume behind the dam is actually water, trapped in the spaces between the sand; allowing an improved groundwater storage capacity. The water harvested by the rain is filtered when it passes through the sand, improving the water quality following the same principle of a slow sand filter.

Further evidence to demonstrate sand dam water is clean solidifies what the communities we work with have been telling us for a long time – that the water from sand dams is potable.

92.3% of sand dams that have a Rowa Handpump installed provide water that is completely free of faecal coliforms and bacteria

Dabane Trust, our partner in Zimbabwe (pictured) have found that 92.3% of sand dams that have a Rowa Handpump* installed provide water that is completely free of faecal coliforms and bacteria, also having acceptable levels of turbidly (cloudiness of the water) – importantly, this meets WHO’s standards for clean water consumption and therefore has no risk for the consumer.

The remaining 7.7% of dams tested are considered as having low risk according to WHO standards, which will also have a substantial difference upon the health of the communities we work with.

The data also shows that we are contributing to Sustainable Development Goal (SDG) 6: To ensure availability and sustainable management of water and sanitation for all.

With better quality of water comes less illness, and less illness brings a wealth of opportunities in income generation, education and many other areas of life – breaking the cycle of poverty and sustainably improving the lives of dryland communities.

Note: Rowa Handpumps* are a novel water abstraction technology created by Dabane Trust. Dabane are looking to go global with the technology, implementing it in other countries including Mozambique and Colombia.

£10 a month could provide safe water for life for one person, every month

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£10A monthly gift of £10 could provide clean water for life for one person, every month.

Supporting people in drylands to build sand dams, which provide a local supply of water, means that less children die each year from curable diarrhoea and women no longer have to bare this burden. Can you help by making a donation that will stop the suffering of communities living in drylands?

Related

Becky Little and Jason Maddrell helped to build a sand dam on an Excellent expedition in 2012. They returned to lead the Excellent 2016 expedition and visited the same community four years’ on, and were astonished to see how much the area has changed.

The results of a new sand dam are astonishing to see - a green oasis in the midst of a barren and parched landscape. This community has been using the water from the dam for growing vegetables and keeping their livestock healthy.

For rural women in the world’s drylands, life is defined by the burden of collecting water. For the old and the young, the sick and the healthy, it is a chore with no relief. Even when pregnant, women must trek over long distances in order to provide their families with water.

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Read about our plan to directly support other organisations to build sand dams, in turn, realising our vision to support millions of the world’s poorest people by helping them to transform their own lives through water and soil conservation in drylands.